應用於第五代行動通訊之毫米波雙頻及寬頻功率放大器研究

Abstract

本論文分為三個部分，都是應用於第五代行動通訊系統的毫米波雙頻及超寬頻功率放大器。 第一個部分呈現了使用 0.15 微米砷化鎵假型高速場效電晶體製程設計的雙頻段功率放大器。此電路利用最佳化匹配路徑的分析使得匹配網路在兩個操作頻段的損失能夠最小化，讓整體功率放大器在兩個頻段都有很好的功率特性。 第二個部分提出了使用 0.15 微米砷化鎵假型高速場效電晶體製程設計的超寬頻功率放大器。此電路利用等效磁耦合共振腔得到寬頻的功率特性，並且利用輸入及級間匹配電路作小訊號濾波，使得小訊號也有寬頻的響應。此外，此部分也有討論在功率結合的架構下，輸出匹配必須要在適當的參考平面設計才能夠達到寬頻的阻抗匹配。此電路的量測結果有 75%的小訊號 3-dB 頻寬以及 51%的飽和輸出功率 1-dB 頻寬。 最後一部分提出了使用 90 奈米金氧半場效電晶體製程設計的雙頻段及雙模式功率放大器。此電路的功率級採用固定最佳負載的偏壓方式切換高功率模式及低功率模式，因此設計上可以只用一組匹配網路讓兩個模式都達到最佳的功率特性，匹配網路則是利用最佳化磁耦合共振腔設計，使得兩個頻段都可以在最小損失的情況下達到匹配的目的。此外，在驅動級設計時，利用閘極偏壓的選擇讓振幅對相位失真與功率級反向達到補償效果，以改善整體線性度。

This thesis is divided into three parts, all of which are millimeter-wave dual-band and ultra wide-band power amplifier used in the fifth-generation (5G) communication system. In the first part, a dual-band power amplifier fabricated in 0.15-μm GaAs pHEMT process is presented. The concept of optimal matching contour is used in the design of matching network to minimize the loss in both operating frequency bands, thus, the power amplifier achieve good power performance in both frequency bands. In the second part, an ultra-wide band power amplifier fabricated in 0.15-μm GaAs pHEMT process is presented. The equivalent magnetically coupled resonator is adopted to obtain wide-band power performance, and the input and inter-stage matching network is designed for small signal gain-flatness to achieve wide-band small signal response. Besides, this part also discusses that under the power-combining structure, the output matching network must be designed in an appropriate reference plane to achieve wide-band impedance matching. The measured results show 75% small signal 3-dB bandwidth and 51% saturated output power 1-dB bandwidth. In the last part, a dual-band and dual-mode power fabricated in 90-nm CMOS process is presented. The constant-Zopt bias switching method is adopted in the power stage to switch between high-power and low-power mode, so both modes can achieve best power performance with only one set of matching network. The matching networks are designed by optimized magnetically coupled resonator to achieve dual-band impedance matching with minimum loss. Besides, the gate bias of driver stage is designed for the reverse AM-PM distortion to compensate the distortion of power stage to improve overall linearity.